X-ray apparatus



Jul 5, 1932.

A. 3 WANTZ it -RAY APPARATUS 2, sheets-Sheet 1 Filed Sept. 6, 1927 WimpI I 1 y k \NVENTOK Juuus a. \Jmh'z.

Torin Jul 5, 1932. J. B. WANTZ ,86 4

X-RAY APPARATUS,

Filed Sept. 6. 1 927 2 Sheets-Sheet 2 \NVENTOK Patented July 5, 1932UNITED STATES PATENT OFFICE JULIUS B. WAN 532, OF OAK PARK, ILLINOIS,ASSIGNOR TO GENERAL ELECTRIC X BAY CORPORATION, OF CHICAGO, ILLINOIS, ACORPORATION OF NEW YORK X-RAY APPARATUS Application filed September 6,1927.

The present invention relates to X-ray tubes and the like. It hasprimarilyto do with means for giving notice to an operator of a tubethat such tube has become overheated. It may provide means for causingthe electromotive force actuating the tube in use to be shut off as anincident to such overheating, or further overheating, and also, it maycomprise a signal means and a means for de-energizing the X-ray tube inoperation, or a combination of both.

Very high efiiciency is being obtained by the employment of X-ray tubesand correlated apparatus. New results have been made possible byimmersing an X-ray tube and sometimes the transformer or transformersand other apparatus in association with such X-ray tube, in an oil bathor in a vessel containing transformer oil. The invention as disclosed inthe illustrations is,

therefore, adapted for use in connection with oil immersed as well asconventionally mounted tubes.

In oil immersed apparatus, a suitable win- (low or windows, eithertransparent, translucent, or opaque to actinic light, but trans parentto X-light are provided in the containers or vessels for the tubes sothat the efliciency of the X-ray is not affected by its oil immersion.One difliculty with such apparatus has been the inability of an operatorto know by external manifestion the precise performance of the tube inuse. This difliculty includes an inability of an operator of a tube tolearn instantly whether there is an excessive flow of electromotiveforce thereacross. I

Overheating of tubes has beenfrequent, with the result that puncturedtubes and other disastrous results have frequently occurred.

In none. of the oil immersed devices now upon the market is a visible oraudible means supplied for association with an oil-immersed apparatuswhereby an alarm to the operator is given as an incident to excessiveheating of a tube.

There have been a number of devices introduced for the purpose of addingsafety to combinations of X-ray apparatus. These Serial No. 217,664.

divers apparatuses include means for controlling the electromotive forceimpressed upon the electrodes of an X-ray tube. None of these devicesoes to the extreme hereinafter referred to, namely, the provision of ameans for giving notice to an operator that the tube is overheated, andfor de-energizing an X-ray tube or a transformer in associa tiontherewith as an incident to such overheating of a tube or as an incidentto the continued excessive heat in the tube after actuation of a visibleor audible signal.

The present invention, therefore, has to do with the combination with anX-ray outfit, conventional or oil immersed, firstly, of means forindicating an excessive heating of a tube, such means being a visible oraudible signal; secondly, a safety means for the tube thermostaticallyor otherwise actuated to shut off the electromotive force impressed uponthe apparatus; and thirdly, a combination of the two previouslymentioned functions.

The signal and safety means may operate concurrently but preferably theshould function subsequently to the former. The device, while remainingwithin the scope of the invention, may contain 'one or the other of thefunctions referred to, or a combination of two. In its simpler and morespecific application, the invention comprises a means for signaling toan operator an excessive temperature in an X-ray tube in process ofoperation; When such excessive flow continues, the apparatus may beadapted to de-energize the tube. The two functions may be independent,correlated, or concurrent in their operation.

The objects of the invention, in part, include the following:

The combination with an X-ray tube of signal means whereby an excessiveflow of current is communicated to an operator by visual, audible, orother manifestation;

The combination with an X-ray tube of safety means whereby theelectromotive force energizing said tube is shut ofl from such tube whena dangerous flow of energy therethrough occurs;

The combination with an oil-immersed latter X-ray tube of an alarmmechanism adapted to be actuated coincidently with the presence of anexcessive heat in the tube or excessive flow of current through suchX-ray tube;

The combination with the anode of an X-ray tube of means adapted to beactuated as an incident to an impression of excessive electromotiveforce upon the electrodes of such tube, whereby such electromotive forceis modified, actuates a visual or audible sig nal, is reduced or isotherwise altered;

The combination with an X-ray tube of means adapted to be oil-immersedand in association with such tube whereby the flow of excessive energythrough said tube is communicated to an operator of the tube;

he combination with an X-ray tube of oil-immersed means in associationwith such tube whereby a flow of excessive energy through said tube isarrested upon becoming dangerous to the operation of said tube;

The combination with an X-ray tube of means whereby knowledge ofoverheating of the tube is communicated to an operator and a the furtherheating of said tube is arrested when dangerous to the operation of saidtube; and

The combination with an X-ray tube of an alarm adapted to communicate toan operator a notice that the tube in use is becoming overheated. These,and such other objects as may hereinafter appear, are obtained by thenovel combination of the elements comprising the invention, theconstruction of the divers parts, and the arrangement thereof withrespect one to another.

Several embodiments of the invention are disclosed in the accompanyingdrawings, in which Figure 1 is a schematic representation of anoil-immersed apparatus adapted to carry out that part of the inventionwhich sug gests the shutting off of electromotive force from a tubewhich has been over-heated;

Figure 2 is a schematic fragmentary detail illustrating a second form ofsuch invention;

Figure 3 is another schematic fragmentary view disclosing an additionalform which such invention may take;

Figure t is an additional fragmentary schematic detail of another formwhich the invention may take;

Figure 5 is a fragmentary schematic View of a second form of theinvention and in which an audible signal is operated;

Figure 6 is an end elevation, partly in section, of another form of theinvention in which the tube is de-energized.

Like reference characters are used to designate similar parts in thespecification which follows and in the drawings.

For a ready understanding of the first illustrated form of the inventionand those forms of the invention in which a tube is deenergized, aschematic representation of an apparatus embodying the invention and ofthe X-ray circuits and apparatus in association therewith and found inFigure 1 should be examined.

lVithin a tank or other suitable container A, and having a cover B, thelatter being provided with a window C, an X-ray tube D and itsassociated apparatus are disposed. This is the general arrangementgenerally followed in the other forms of the invention shown in Figures1 to l, inclusive, and in F igure 6.

An X-ray tube D is suitably mounted in the container A so that theX-rays generated in said tube D will be projected through the window Cin cover B.

Said X-ray tube D includes an anode E. The tube D disclosed is of thehot cathode type and is provided with a cathode F having theconventional filament G. \Vithin the container or box A, there is alsodisposed a main transformer H which is adapted to generate theelectromotive force impressed across the anode E and cathode F; andalso, a filament transformer I which is adapted to provide theelectromotive force used to heat the filament G in forming a part ofcathode F. The wiring system within the container A so far described andin so far as it relates to the main transformer H, the filamenttransformer I, the anode E and the cathode F, is conventional.

Also disposed within the container or box A, is a thermostat, or anequivalent heatafi'ected apparatus, designated M. Associated with thethermostat M is an insulated rod N at the end of which is a contact 0.

Said contact 0, when moved to the left is energized is adapted to closea circuit to the main transformer H, whereby electromotive force isimpressed upon the primary of the main transformer H. The shortcircuiting of said holding coil tie-energizes the tube D. In the eventof over-heating the tube D, the thermostat M moves the rod N to the leftto bring together the contacts 0 and P whereby a switch R controlled byrelay Q, and opening the circuit to the primary of transformer H, isopened. In place of switch and relay, as described, the closing ofcontacts 0 and I may be used to close a light circuit providing a visualsignal, or to close a bell circuit, providing an audible signal, aspreviously indicated.

In the several apparatuses hereinafter referred to and illustrated inFigures 2 to 4, inclusive, the same general circuit arrangement exists.It is contemplated that there shall be associated with the anode E, oranother part of the apparatus, athermostat or other heat affectedelement M adapted to be actuated by excessive heat, which heat-actuatedelement is adapted to set in motion the necessary parts to automaticallyactuate a switch R to the transformer whereby the circuit to suchtransformer H, which is closed while the tube D is in operation, isopened.

The theory of operation in the present invention is that in anoil-immersed X-ray outfit the place where the flow of excessive energythrough the tube D will be first noticed is either upon the anode E ofthe X-ray tube D, or in ijuxtaposition thereto, and that such excess 0energy will demonstrate itself by the generation of heat in such anodeE, and that such heat is dissipated in the insulating oil surroundingsuch anode E.

The anode E is invariably of a material rapidly dissipating heat, thatis, one of high heat conductivity. The portion of such anode E externalto the tube D, shortly after the impression of excessive electromotiveforce across said anode E and cathode F, will become highly heated. Thethermostat M is in association or in juxtaposition to said anode E, andit is therefore adapted to be operated as an incident to the increasedheat in the exposed portion of the said anode E when the temperaturethereof exceeds a certain degree. Of course, it is recognized that theapparatus is not sensitive enough to prevent a sudden excessive flow ofenergy through the tube D. To be actuated, it is necessary that there bean accumulation of excess energy, which accumulated excessive energytakes the form of heat energy.

For convenience, the temperature at which the apparatus is operated willbe called the critical temperature. This critical tempera.- ture must bederived from the accumulation of excess energy.

It is to be noted that the transformer oil which surrounds the exposedend of the anode E will become hot quickly and that the heat of theanode E will be communicated to such oil in the tank promptly and withsuch rapidity that any device actuated as the result of overheating ofthe transformer oil will be highly efficient.

Thus, when there is a flow of energy across the tube D in excess of theamount prescribed for the particular apparatus, the anode E will beoverheated, and the heat in said anode E will heat the thermostat M orthe transformer oil whereby the thermostat M will be affected by suchexcessive heat. Such thermostat M will energize, either Within thecontainer A or external thereto. through operating mechanisms, a relay Qwhich affects a switch R in theline to the main transformer H. Suchswitch It will open the circuits between the transformer II and thesource of electromotive force by which said transformer H is energized.In

present day practice, such source of electromotive force generally is alocal power station.

It is quite manifest that the device may assume other forms than thoseherein shown, but that the principle upon which the invention operatesis the same in each case. That principle, restated, is that the anode ofan X-ray tube becomes hot earlier than any other part of the tube and isa criterion for determining the accumulation of excess energy. A secondand quite convenient means of actuating a device. of the character heredisclosed is to cause its actuation when the transformer oil which isused for insulation in the X-ray apparatus becomes excessively hot.

By associating a thermostat with the anode of a tube or with anotherpreferred part of a tube, or with the transformer oil, it is thuspossible to establish or break electrical contacts mechanically orelectrically within or outside of the container A, whereby to operatedirectly or through an independent circuit, a switch adapted to open theclosed circuit to the transformer H. Such theory includes the employmentof a means for opening such transformer circuit by direct movementbrought about by the effect of heat upon a thermostat or other element.

In Figure 2, there is shown a type of anode E to which a'sylphon orsimilar thermostat M is directly secured. Excessive heat in the anode Ecauses the thermostat M to mechanically operate an insulation rod Nsecured at its center. Said rod N has at its end a movable contact 0,such movable contact when actuated by the rod N being adapted to providecontact with a stationary contact P and thus close the previouslydescribed circuit to the relay Q.

Rod N'necessarily is of insulation material and of such length thatthere is no possibility of high tension from the anode E reaching thelow tension circuit energizing transformer H or relay Q.

In Figure 3, a different type of thermostat M is shown. In this form thethermostat M is of the liquid type and doughnut shaped and is adapted toactuate a rod N secured at doughnut type, and it is thus enabled to en-,7 close the exposed end of the anode E. Irrespective, then, of theposition of the container A, the thermostat M will be instantly affectedby excessive heat in anode E and caused to actuate the rod N.

In Figure 4, is another thermostat M like that shown in Figure l andwhich may be employed in the tank A whereby to actuate a rod N ofinsulating material to actuate a movable contact which movable contactis adapted to be moved toward a fixed contact P, whereby a circuit to arelay Q may be closed to break the circuit in the low tension line totransformer H.

Upon the opening or closing of the circuit to the relay Q, the switch isopened, cutting oft current flowing through the trans former H.

lVhether there is or is not a diflerence the transfer of heat from theanode E thermostat M due to convection currents in the transformer oilused in the container A is immaterial in an apparatus such as is shownin Figure 4. In this form of the invention there is illustrated what maybe termed a floating thermostat, for the thermostat M is disposed upon abracket S which comprises an arm having a trunnion T adapted to besecured in anode E by lock screw U operating in groove V encirclingtrunnion T.

The weight of the thermostat M is such that it floats in the tank A,hence, as the tank A is moved, the thermostat M floats above the exposedend of anode E. It may be advantageous that the thermostat ld he sodisposed directly above the exposed portion of anode E. As the containerA is moved from one position to another and turned, the thermostat Mwill continue to be situated above the anode E because of the freedom ofmovein to ment of such thermostat M upon the loosely connected bracket Sriding in anode E.

An insulating rod N is actuated by thermostat M and moves a contact 9secured thereto into engagement with a fixed contact P which is mountedupon a second arm W of bracket Thus high efficiency may be obtained inan apparatus such as is illustrated in Figure at, for the thermostat Mis adapted to remain in a position for most eflective use irrespectiveof the ordinary movements which may be made of the container A in whichthe principal parts of the apparatus are disposed. Most of suchmovements are about the axis of the tube D and therefore may becompensated for in the movement of bracket S.

.Wiere contacts 0 and P, or their equivalents, are disposed within theinsulating liquid in container A, such contacts may be very closelyassociated so that slight movement thereof by the thermostat M willestablish electrical connection between said contacts. In 'iew of theinsulating qualities of the media called transformer oil, it may bedesirable to employ upon one or both contacts 0 and P a sharp point.here only one of the contacts 0 or P is so provided, as is shown inFigure 3, movement thereof against the surface of the other contactestablishes an electrical connection through such point or points andthe impinged surface of the other contact. Where both contacts areprovided with points, the points are ordinarily arranged to come intocontact one with another, thus providing a sharp contact for the flow ofelectromotive force therebetween.

The establishment of contacts under these conditions is not seriouslyaffected by reason of the contacts being immersed within the transformeroil or media used as an insulation with respect to the main and filamenttransformers of the apparatus and the remainder of the apparatuscontained within the box or container A.

In another form of the invention such as is shown in Figure 5, a signalis made audible to an operator as soon as the tube becomes overheated.This type of the invention is adapted for use in connection with tubesnot oil immersed as well as to oil immersed tubes. Ordinarily a fewseconds of overheating of a tube will do no damage thereto, hence, wherethe operator is making fluoroscopic examination and has gone so far withsuch examination that the shutting off of the current instantly woulddeprive such operator of the benefit of eiiort so far made to completethe desired examination, the operator may be provided with a meanswhereby he is informed that the tube is over heating and that hemustdiscontinue his examination shortly. The duty of terminating theenergy flow is then transferred to the operator who may manually open aswitch to the transformer H and discontinue the flow of energy. At thesame time, there may be a combination in the apparatus of such signalmeans and an automatic safety means actuated at a definite time afterthe signal is given, or after the excessive heat is increased whereby,independently of any act on the part of the operator, the energy to thetube is terminated.

Integral with or secured to the anode E as shown in Figure 5, is a heador flange 10, circular in configuration or any other desired shape.Attached thereto peripherally is a cap or cover 11. Through an aperturein said cap, a conduit 13 passes. The walls of the cap 11 about theaperture are insulated by an insulating bushing or collar 14 wherebydirect contact between the conduit 13 and the cap 11 is avoided.

Upon the flange is a lug or boss 15 from which projects a pivot point16. At the other side of said flange 10 is a boss 17 upon which issecured a composite strip of laminated heat affected materials havingdifferent coefficients of expansion. Normally such strip is parallel tothe face of flange 10.

An insulating base 19 has attached thereto a bifurcated spring-likemember 20 which is dapted to be seated upon the pivot 16 and the rec endof the laminated strip 18.

Depending from the base 19 is an arm 21 terminating in a contact 22.This comprises the movable contact in this form of the apparatus. Thefixed contact thereof is inclicated at 23 and it is mounted upon theflange member 10, as is shown in the drawings.

Upon and attached to the opposite side of cover 11 is a yoke or base 24in which is secured the coil 25 of a buzzer, the clapper member of suchbuzzer being designated 26.

The conduit 13 within the cover 11 is divided into two sections, onesection 27 running to the coil 25, and the other section 28 going to themovable contact 22.

Another conduit 29 extends from the anode E to the opposite side of thecoil 25, and has as apart thereof a branch 30 which is con-- nected tothe fixed contact 23.

When excessive heat is generated in the tube in operation, the anode Ethereof is a result of accumulated excessive energy becomes hot. Suchheat is transferred to the laminated strip 18 which is adapted to bendaway from the face of the flange 10 whereby to move the frame 19 havingas a part the bifurcated member 20, the movement thereof being in adirection whereby the contacts 22 and 23 are separated.

The current, previously flowing along the conduit 13, the conduit 28,the contact 22, the contact 23, the conduit 30, and anode E, which is ofhigh potential, can no longer flew in the circuit described. Its flowmust be through the conduit 18, the conduit 27, the coil 25, and conduit29. In this manner the coil in the buzzer is energized as is customaryin buzzer mechanism, whereby the clapper 26 is set into motion toprovide an audible signal for the operator.

The operator may shut off the electromotive force to the tube as soonthereafter as he desires. Should he continue to impress electromotiveforce across the tube D after a sig nal is given, the disastrous resultswhich may follow are wholly a matter of his own responsibility. Thefunction of the apparatus disclosed is complete when the audible signalis created whereby the operator is afforded an opportunity todiscontinue the impression of the electromotive force upon theapparatus.

When the device, after overheating, is

allowed to cool, the heat affected element 18 will resume its normalposition and concurrently with the movement of the frame 19inwardly, thecontacts 22 and 23 may again 1111- pinge and the current allowed to flowdirectly from the anode E to the conduit 13 in the manner hereinabovedescribed.

It is quite manifest that an apparatus of this character may be added tothe usual X-ray tubes by a slight modification of the anodes thereof, orthat the flange member 10 may be made attachable to standard anodes. Thewhole device isycompact and self-contained and is relatively simple tomanufacture. Its eflicacy is instantly apparent as an aid to theeffective operation of tubes in that it affords an operator an instantsignal when a danger point has been reached.

In Figure 6 a further modification of the apparatus is disclosed. Uponthe side of the container A is mounted a cell or chamber 60. Within thecell is a bellows 61, which is adapted to distend as an incident to theexpansion due to heating of the transformer oil contained within thevessel A. A plunger 62 is arranged at a convenient point upon suchbellows 61.

At one side of the chamber 60 is a boss 63 to which is secured a springmember 64 car rying a movable contact 65. The plunger 62 upon thebellows 61 is adapted to engage upon the spring member 6 1 and uponexpansion of the oil in chamber A the member 64: is pushed in aleft-hand direction (in Figure 6) whereby the contact 65 is moved in asimilar direction.

Normally said member 65 is in impinging contact with a fixed contact 66,also Within the chamber 60.

The electrical circuit to the transformer includes the conduit 67, whichis directly connected to one side of said transformer.

Into the chamber 60, the two branches of a conduit 68 are introduced,one of said branches being connected to the movable contact 65 and theother to the fixed contact 66. One branch of conduit 68 is connected tothe other side of said transformer, while the other branch of saidconduit, like conduit 67 is connected to the source of electromotiveforce.

When a dangerous overheating of the tube within the tank A occurs, thebellows 61 functions to disconnect the contacts 65 and 66 whereby thecircuit established by the two branches of conduit 68 is broken, thuscutting off the electromotive force which is used to energize thetransformer within the chamber A.

I claim:

1. The combination with an X-ray tube having an anode and a transformerused in connection therewith of a thermostat secured to said anode, arelay, contacts controlled by said thermostat, and a circuit to saidrelay in which said contacts form a part, the overheating of said tubebeing adapted to cause said thermostat to close said contacts to saidrelay to open the circuit to said transformer.

2. In combination, an X-ray tube having an anode, a transformer, athermostat upon the outer end of said tube and adapted to be actuated bysaid tube as an incident to the overheating thereof, a relay adapted toopen the circuit to said transformer, and a circuit to said relay andcontrolled by said thermostat.

3. The combination described in claim 2, and in which said thermostat isadapted to float above the anode of said tube.

JULIUS B. WANTZ.

